Pull-off yoke



June 16, 1931. I w SCHAAKE 1,810,733

PULL OFF YOKE Filed May 20, 1930 INVENTOR ATTORNEY Patented June 16,1931

UNETEE STATES PATENT orrica WILLIAM SGHAAKE, F PITTSBURGH, PENNSYLVANIA, AssIsuoR- rc WESTINGHOUSE ELECTRIC & MANUFACTURINGCOMPANY, AooRro TmN or PENNSYLVANIA PULL-OFF YOKE Application fil ed May 20, 930- Serial No. 453,939. a

My invention relates to supports for trol-.

ley conductors and'more particularly to corn ductor supports which are adapted for use on curves and when a bow or sliding current collector is used.

An object of my invention, generally stated, is to provide an improved trolley-conductor support which will be simple and effective in operation and which may be readily and economically manufacture A more specific object of my invention is to provide a trolley-conductor support which will be light in weight and mechanically strong.

Another object of theinvention is to prevent the bending of a pull-off yoke'as a result of the pull of the trolley conductor.

For a fuller understanding of the nature and objects of my invention, reference may be had to the following detailed description, taken in connection with the accompanying drawings in which:

Figure 1 is a view, in side elevation, of a pull-off yoke constructed in accordance with my invention;

Figs. 2, 3 and 4 are enlarged sectional views,

taken along the lines II-II, IIIIII, and

IVIV, respectively, of Fig. 1, and

Fig. 5 is a top plan view showing pull-oif yokes applied to the supporting of a trolley conductor from a catenary cable on a curve.

Referring now to the drawings, the pull-off yoke 9, as illustrated, comprises a section of metal tubing 10 which may be made of any Car suitable metal, but preferably of aluminum alloy, as it is light in weight. One portion of the tubing 10 is round and the end is adapted to receive atrolley clamp 11 for supporting a trolley conductor 12. Any suitable clamp of a standard design may be utilized.

In order that the pull-0E yoke shall not be struck by a pantograph bow 13 of a moving car or locomotive, it is curved near the opposite end from the one that carries the trolley conductor, as shown in Fig. 1, thereby providing ample clearance for the pantograph bow. The pull-oif yoke may be attached to a catenary or messenger cable by any'suitable hook or clamp, which may be secured to the opposite end from the tubing, which is the point of maximum the one that carries the trolley clamp. p r

= In catenary construction, it is desirablethat the conductor supports be as light'as possi 1 ble in order that the trolley conductor may rise and fall as a current collector passes along it, thereby providing an overhead trolley system without hard spots. In systems having hard spots, the conductor is subjected to hammer blows, which are delivered thereto by the rapidly moving currentcollecting devices and tend to cause excessive heating and wear.

It is necessary that the pull-off yokes have sufficient strength tosupport the weight of the conductor and to withstand the side pull which is exerted when the conductorextends around a curve. In order to increase the strength of the pull-off yoke at the .bend in bending moment resulting from the side pull of the trolley conductor, without greatly increasing the weight of the pull-0E yoke, a reinforcingsleeve 14 is provided, which is telescopcd over the tube 10 and extends along itscurved, portion.

. In order. to still further increase the strength of the pull-off yoke, without increasing' its weight, to enable it to withstand the side pull ofthe conductor, which has a tendency to straighten out the bend in the yoke, the curved portion ofthe yoke is flattened or expandedvertically, as shown in the drawings. This increases the section modulus with respect to the horizontal axis of the sec tion and, therefore, increases the bending moment which the yoke can withstand without being distorted.

An application of the pulloff yoke in catenary curve construction is illustrated in Fig. 5 whichshows the trolley conductor 12 supported by a plurality of the pull-off yokes, .which, in turn, are suspended from a catenary ormessenger cable 15. In this instance, the cable 15 is secured to supports 16 by means of cables 17; however, any of the well known methods of supporting catenary cables may be utilized,

In'order that the pull-0E yoke may be suspended at an angle conforming to the direction of the resultant of the horizontal and vertical stresses on the trolley wire, the trolley clamp 11 is adjustably mounted on the tube 10 by means of a bolt 18. The pull-off yoke may, therefore, be mounted at an inclined angle, While the clamp 11 is in an upright or vertical position.

Since numerous changes may be made in the above-described construction and diiferent embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. A pull-oil yoke for a trolley conductor comprising, in combination, a section of metal tubing curved near one end, a section of metal tubing telescoped over the curved portion of the tubing to reinforce it, both of said sections being expanded vertically along the curved portion to increase the section modrb lus with respect to the horizontal axis, there by increasing the mechanical strength of the pull-ofi yoke.

2. A pull-off yoke for a trolley conductor comprising, in combination, two metal tubes, one being telescoped inside of the other for reinforcing, both of said tubes being curved near one end and expanded vertically along the curved portion to increase the section modulus with respect to the horizontal axis of the tubes, thereby increasing the strength of the pull-ofi yoke.

3. A pull-off yoke for a trolley conductor comprising, in combination, a metal tube curved near one end, and a reinforcing sleeve disposed along the curved portion to increase the mechanical strength of the pull-01f yoke.

4. A pull-off yoke for a trolley conductor comprising a metal tube curved near one end, said tube being expanded vertically along the curved portion to increase the section modulus with respect to the horizontal axis of the tube, thereby increasing the mechanical strength of the yoke.

5. A trolley device for supporting a trolley conductor comprising, in combination, a metal tube curved near one, end, a reinforcing sleeve disposed along the curved portion 7 to increase the mechanical strength of the tube, and a trolley clamp for securing the trolley conductor, said clamp being adjustably mounted on the metal tube.

In testimony whereof, I have hereunto subscribed my name this 15th day of May, 1930.

WILLIAM SCI-IAAKE. 

